7-10% of the male population suffer from red/green colour blindness, a condition which means the person cannot distinguish between red and green. It is the most common form of colour blindness and is primarily hereditary. It is associated with the X chromosome which is the reason it is predominantly male condition. Blue colour blindness is also hereditary but is much more uncommon and affects men and women equally.
The following pictures are taken from a blog (The Brick Castle) and are a great depiction of how people living with colour blindness see the world.